DSA-4892 python-bleach - security update

It was reported that python-bleach, a whitelist-based HTML-sanitizing library, is prone to a mutation XSS vulnerability in bleach.clean when svg or math are in the allowed tags, 'p' or br are in allowed tags, style, title, noscript, script, textarea, noframes, iframe, or xmp are in allowed tags and 'strip_comments=False' is set.